Mixed triglyceride compositions



United States'Patent O "ice 3,027,259 MIXED TRIGLYCERIDE COMPOSITIONS Fredric J. Barn, Cincinnati, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Filed Jan. 5, 1960, Ser. No. 490 5 Claims. (Cl. 99-118) This invention relates to glyceridic oils eminently suitable for salad oil applications.

More particularly, this invention relates to glyceridic oils which comprise mixed esters of lower and higher molecular Weight fatty acids and which are particularly suitable in the preparation of mayonnaise compositions having an outstanding degree of emulsion stability and improved oxidative stability.

This application is a continuation-in-part of applications Serial No. 500,019, filed April 7, 1955, and Serial No. 500,295, filed April 8, 1955.

Edible liquid oils are generally classified as cooking oils or salad oils. In the United States a rather sharp differentiation is made between these two classes, the term salad oils referring to oils which will remain substantially liquid in a refrigerator at 40 to 45 F., and which will produce mayonnaise emulsions reasonably stable at low temperatures. A cooking oil on the other hand, may solidify completely at temperatures of 40 to 45 F. and will not normally be capable of producing a stable mayonnaise emulsion.

Mayonnaise can readily withstand temperatures of 50 F. without emulsion failure. On occasions when it is subjected to substantially lower temperatures such as those which may be encountered when the temperature of a mechanical refrigerator is lowered for certain purposes or in shipping or storage in the winter months, emulsion failure, as evidenced by oil separation, can readily occur. Additional difficulties may also be encountered with mayonnaise compositions because of the susceptibility to oxidation of some of the oils which are commonly used in preparing such compositions.

it is an object of this invention to provide an oil composition which, when used as the oil constituent in a mayonnaise emulsion, imparts to the mayonnaise improved emulsion stability at low temperatures.

Another object of this invention is to provide an oil suitable for use in salad oil applications which has improved oxidative stability.

A still further object of this invention is to provide mayonnaise compositions which are characterized by outstanding emulsion stability and improved oxidative stability.

Other objects and advantages will be apparent from the following detailed description.

It has been found that the objects of this invention can be achieved by providing an oil comprising mixed triglycerides of combined high molecular weight and low molecular weight fatty acids and by utilizing such oils in the preparation of mayonnaise emulsions.

In the oils of this invention each of the combined low molecular weight fatty acids of the mixed triglycerides is selected from the group consisting of acetic, propionic, butyric and caproic acids. The combined high molecular weight fatty acids of the oils of this invention are derived from vegetable oils of the lauric acid group and their hydrogenated products and may include caprylic, capric, lauric, myristic, palmitic, stearic and corresponding acids containing 1 or 2 carbon to carbon double bonds. (Classification from Industrial Oil and Fat Products," second edition, A. E. Bailey, p. 133.)

In order to achieve the aforementioned objects it has been found that the mixed triglycerides of the glyceridic 3,027,259 Patented Mar. 27, 1962 oils of this invention should contain from about one-half to about two-thirds of the aforementioned combined low molecular weight fatty acids on a molar basis. Also, if desired, these oils may be rendered substantially free of triglycerides, the combined fatty acids of which are wholly of the group of low molecular weight saturated fatty acids specified above.

The oils of this invention can be conveniently prepared by interesterifying a mixture of triglycerides, the combined fatty acids of which are wholly of low molecular weight, e.g., triacetin, tripropionin, tributyrin, tricaproin and mixtures thereof, or mixed wholly low molecular weight triglycerides such as monobutyro-diacetin, and a high molecular weight triglyceride oil of the lauric acid group as noted hereinbefore. This interesterification is accomplished in a known manner by intimately contacting the said mixture with an interesterification catalyst, e.g., sodium methoxide, until substantial rearrangement of acyl groups in the triglyceride molecule has taken place. The reaction is then discontinued, by either removing or inactivating the catalyst, and the product is normally treated to remove substantially all of the unreacted wholly low molecular Weight triglyceride.

By way of example, a more detailed description of a preparation utilizing triacetin as the low molecular weight triglyceride is given immediately below.

To a refined and dried or deodorized vegetable oil of the lauric acid group in the liquid state is added the selected quantity of triacetin. The amount of triacetin is chosen on the basis of the content of acetyl groups desired in the final interesterification product. To the mixture of oil and triacetin is added about 0.3% of a low temperature interesterification catalyst, such as sodium methoxide, sodium potassium alloy or sodium metal. With agitation the two-phase mixture rapidly becomes homogeneous as interesterification occurs. The interesterifying mix is maintained at about F., or higher if necessary, to obtain homogeneity. Within about onehalf hour random esterification is substantially completed. While a substantial degree of interesterification should be eiiected, it is not imperative that the reaction go to final completion, i.e., equilibrium. The interesterification is discontinued by inactivating the catalyst by acidulation or by water-washing. After acidulation, water-soluble salts and free excess acid can be removed by a Water-washing step, or, if desired, any free acid can be first neutralized with alkali. Alternatively, an alkali refining step is sometimes introduced after acidifying the rearranged mixture. Water-washing removes some of the triacetin present but it is sometimes desirable to remove susbtantially all of the triacetin from the acetincontaining product. This can be accomplished by deodorization.

The rearranged mixture is complex in composition comprising triacetin, high molecular weight triglycerides, monoacyl diacetins, and diacyl monoacetins. If it is desired to obtain a Wholly diacetyl triglyceride product, the unreacted tr-iacetin and other low boiling constituents which remain in the rearranged mixture after inactivating the catalyst and washing are first removed. This is usually accomplished through distillation under a pressure of 2 or 3 mm. of mercury while passing a stream of inert gas, e.g., nitrogen or steam through the mixture. Triacetin readily distills at this pressure before a temperature of about 300 F. is reached. Following this step a fraction consisting of high molecular weight diacetyl triglycerides is isolated. In order to do this, the temperature of the steam distillation, or other distillation, is raised and/or the pressure is reduced until diacetyl triglycerides distill. Where a substantially wholly diacetyl triglyceride product is desired conditions drastic pp. 133l38). .source of the combined high molecular weight fatty acids 'of the triglycerides of the oils of this invention, in conjunction with the fact that the low molecular weight enough to cause distillation of substantial amounts of triglycerides containing less than two acetyl groups must obviously be avoided. The exact temperature of distillation will vary with the particular oil used and with the speed of distillation required.

The residue after distilling off the diacetyl triglycerides is largely a mixture of monoacetyl triglycerides and unreacted high molecular triglycerides and this mixture may be reworked in the process along with unreacted triacetin recovered as noted above.

It is to be understood that the foregoing description is merely illustrative and other methods will readily suggest themselves to those skilled in the art. For example, if desired, a water-washed, dried, and unrefined oil can be used as the starting material. This oil can then be interesterified with triacetin, or one of the other low molecular weight triglycerides hereinbefore mentioned, in the presence of an in-teresterification catalyst. After the interesterification is complete, the catalyst can be inactivated by the addition of water to the interesterified mix and the water and soap stock can be separated by conventional means. This mix can then be hydrogenated to the desired degree in accordance with well known practice. In the event the diacetin fraction of this product is desired this fraction can be separated as hereinbefore noted and hydrogenation practiced after the fraction has been separated.

Other methods for introducing low molecular weight fatty acid radicals into high molecular weight fatty acid triglycerides to provide the glyceridic oils of this invention can, of course, be used as will be evident to those skilled in the. art. A description of additional methods as well as additional interesterification catalysts which are applicable to such methods can be found in U.S. Letters Patent 2,614,937, issued October 21, 1952, columns 10, 12 and 13.

It is also to be understood that the separation of constituent fractions of the interesterification products, e.g., the diacetin fractions, can be accomplished by means other than distillation. For example, crystallization processes or fractional separation utilizing solvents of various types can be employed.

It is well known that the combined fatty acids of the triglyceride oils of .the lauric acid group are relatively saturated acids, e.g., coconut oil is characterized by an iodine value of from about 7.5 to 10.5 and palm kernel oils are characterized by iodine values of from about l623 (A. E. Bailey, Industrial Oil and Fat Products, Therefore, the use of such oils as the combined fatty acids of theoil of this invention are saturated, will result in glyceridic oil characterized by excellent oxidative stability.

Mayonnaise is produced with any of the aforementioned oils by incorporating these oils with vinegar, eggs, salt and other materials in the manner ordinarily employed for this purpose (e.g., in accordance with the standard for mayonnaise of the Federal Security Agency, Federal Register, August 12, 1950, pp. 5227-5232).

'In the industry the efiicacy of a salad oil for mayonnaise production is based upon results of a chill test of the salad oil itself. It is generally accepted that freedom from clouding at 32 F. for 5.5 hours is the bare minimum standard for a salad oil which is satisfactory for use in the preparation of mayonnaise emulsions (standard chill test-official method Cc l153 of the American Oil Chemists Society). It was also believed that the greater the length of time the oil remainder free from clouding when subjected to this test the greater would be the resistance to freezing of the mayonnaise w-ithsuch oils. That is to say, the greater would be the emu ion stability of the mayonnaise.

in view of this criterion, and the fact that vegetable oils of the iauric acid group are substantially solid at norr al room temperatures, it was completely unpredictable that the oils of this group, such as, coconut oil, would lend themselves to the preparation of salad oils and particularly the preparation of oils which impart to mayonnaise compositions incorporating them such outstanding low-temper ature emulsion stability.

It is also significant that whole eggs as well as egg yolks can be used in the mayonnaise compositions of this invention. It is generally recognized that the use of whole eggs as opposed to egg yolks in the preparation of mayonnaise has given rise to difhculties with regard to the low temperature emulsion stability of the mayonnaise. -l[owever, with the particular glyceridic oils specified herein, whole egg mayonnaise which is characterized by outstanding emulsion stability at low temperatures can 'readil y be made. Thus, in addition to the unpredictability of the outstanding emulsion stability of the mayonnaise compositionsof this invention, such mayonnaise compositions olfer substantial economic advantage over those of the prior art in that they allow the substitution of whole eggs for egg yolks without affecting adversely the low temperature emulsion stability of the compositions.

It is to be understood that wherever herein, or in the appended claims, the unmodified word eggs appears it is to be interpreted as including both whole eggs and egg yolks.

In the following examples, which, it is to be understood, are illustrative only, the low temperature stability of the mayonnaise prepared was determined as follows unless otherwise indicated.

After preparation, the mayonnaise is first stored overnight, or from about 16 to 24 hours, at a temperature of 50 F. Following removal from storage after this initial period, it is alternatively stored at 20 F. for varying lengths of time and allowed to thaw at room temperature. After thawing the mayonnaise sample is examined for possible oil separation which is indicative of the resistance of the emulsion to breaking.

Example I One part of refined and dried coconut oil was hydrogenated to an iodine value of 1 and then interesterified by mixing with 1.5 parts of triacetin and 0.3% sodium methoxide catalyst and holding at 140 F. for 20 minutes.

45 :The catalyst was inactivated with water and remaining triacetin was removed by steam distillation at 2 to 3 min. of mercury. Removal of the triacetin was substantially complete at 320 F. The temperature of the mix was then raised and the diacetin portion, which distilled in the range from 340 to 430 F. was separated.

Four parts of refined and dried coconut oil having an iodine value of 10 was interesterified with 10.5 parts of triacetin by mixing with 0.3% of sodium methoxide catalyst and holding at F. for 15 minutes. The catalyst was inactivated with water and the soap formed was separated by filtration. Unreacted triacetin was substantially completely removed by steam distillation at reduced pressure.

The resulting oil had an iodine value of 7.7 and it was determined that 26.4% by weight of the combined fatty acids of this oil were acetic.

This "oil was used to prepare a whole egg mayonnaise constituent, they may also, if desired, be used in combination with other edible oils. Moreover, the oxidative stability or low-temperature behavior of the oils of this invention may be benefitted through the addition of various antioxidants such as tocopherols, butylated hydroxy anisole and propyl gallate, or various crystallization inhibitors, such as lecithin and oxidized (blown) oils.

Having thus described the invention what is claimed is:

1. A liquid glyceridic oil characterized by outstanding oxidative stability and suitable for use in salad oil applications which liquid glyceridic oil consists essentially of mixed triglycerides of combined high molecular weight and low molecular Weight fatty acids, the said combined low molecular weight fatty acids being selected from the group consisting of acetic, propionic, butyric and caproic acids and mixtures thereof, and the said combined high molecular weight fatty acids being derived from vegetable oils of the lauric acid group and their hydrogenated products, the said mixed triglycerides containing from about one-half to about two-thirds of the said low molecular weight combined fatty acids on a molar basis and the said liquid glyceridic oil being substantially free of triglycerides wholly of low molecular weight fatty acids.

2. The glyceridic oil of claim 1 wherein the combined low molecular weight fatty acids are acetic.

3. The glyceridic oil of claim 1 wherein the combined low molecular weight fatty acids are propionic.

4. The glyceridic oil of claim 1 wherein the combined low molecular weight fatty acids are butyric.

5. The glyceridic oil of claim 2 wherein the combined high molecular weight fatty acids are derived from coconut oil.

References Cited in the file of this patent UNITED STATES PATENTS 1,505,560 Grun Aug. 19, 1924 1,558,299 Schwartz Oct. 20, 1925 2,266,591 Eckey et al. Dec. 16, 1941 2,614,937 Bauer et al. Oct. 21, 1952 2,615,159 Jackson Oct. 21, 1952 2,615,160 Baur Oct. 21, 1952 2,627,467 Gooding Feb. 3, 1953 2,627,469 Melnick et al Feb. 3, 1953 2,745,749 Feuge May 15, 1956 OTHER REFERENCES Vicknair et al.: J. Physical Chem., vol. 58, pp. 64-66, January 1954.

Ward et al.: J. Physical Chem, vol. 58, pp. 4-6, January 1955.

Feuge et al.: J.A.O.C.S., vol. 30, No. 8, pp. 320325, August 1953.

Lord: Everybodys Cook Book, Henry Holt and Co., N.Y., 1924, p. 673. 

1. A LIQUID GLYCERIDIC OIL CHARACTERIZED BY OUTSTANDING OXIDATIVE STABILITY AND SUITABLE FOR USE IN SALAD OIL APPLICATIONS WHICH LIQUID GLYCERIDIC OIL CONSISTS ESSENTIALLY OF MIXED TRIGLYCERIDES OF COMBINED HIGH MOLECULAR WEIGHT AND LOW MOLECULAR WEIGHT FATTY ACIDS, THE SAID COMBINED LOW MOLECULAR WEIGHT FATTY ACIDS BEING SELECTED FROM THE GROUP CONSISTING OF ACETIC, PROPIONIC, BUTYRIC AND CAPROIC ACIDS AND MIXTURES THEREOF, AND THE SAID COMBINED HIGH MOLECULAR WEIGHT FATTY ACIDS BEING DERIVED FROM VEGETABLE OILS OF THE LAURIC ACID GROUP AND THEIR HYDROGENATED PRODUCTS, THE SAID MIXED TRIGLYCERIDES CONTAINING FROM ABOUT ONE-HALF TO ABOUT TWO-THIRDS OF THE SAID LOW MOLECULAR WEIGHT COMBINED FATTY ACIDS ON A MOLAR BASIS AND THE SAID LIQUID GLYCERIDIC OIL BEING SUBSTANTIALLY FREE OF TRIGLYCERIDES WHOLLY OF LOW MOLECULAR WEIGHT FATTY ACIDS. 